The current air navigation system has limitations that affect timely identification and localization of aircraft in distress. This leads to ineffective search, rescue, and recovery efforts. To increase the effectiveness of alerting and search and rescue (“SAR”) services, the International Civil Aviation Organization (“ICAO”) has implemented a Global Aeronautical Distress and Safety System (“GADSS”). Information management and procedures within the GADSS framework, such as an Automatic Dependent Surveillance-Broadcast (“ADS-B”), are being evaluated to address the future global tracking requirements.
ICAO and other regulators envision three kinds of aircraft tracking: 1) Aircraft Tracking Normal Operations (“Normal Tracking”); 2) Aircraft Tracking Abnormal Operations (“Abnormal Tracking”); and 3) Autonomous Distress Tracking (“ADT”). The Aircraft Tracking Normal Operations is a possible subset of Air Traffic System (“ATS”) surveillance used for airline operational functions. Normal Tracking occurs continuously from takeoff to landing and tracks where the airplane travels. Information pertaining to a position of the airplane is transmitted at least once every fifteen minutes via a position report. The position report can include information, such as latitude, longitude, altitude, and heading information. If available, surveillance can be substituted for Normal Tracking. The Abnormal Tracking and ADT are triggered by an abnormal event and provide flight location data at least once per minute in response to a trigger. Abnormal Tracking can be triggered when the airplane is in the air or on the ground. If available, surveillance can be substituted for Abnormal Tracking. ADT can be triggered by a very specific set of conditions being defined, for example, by Special Committee SC-229. The ADT is a formal distress signal that initiates SAR protocols. The ADT is independent of aircraft power loss and continues to transmit after a loss of aircraft power for the duration of the flight. It is required that the ADT provides a crash site location within six nautical miles of the crash site (or a one minute minimum update rate). Furthermore, the ADT system cannot be isolated and should be independent of Normal and Abnormal Tracking. However, because all three kinds of aircraft tracking are controllable by the flight crew, or another person, the systems can be disabled or tampered with. Thus, there is a need for a tamperproof avionics system by which an aircraft could be located and/or tracked down in case of an abnormal or distress event.